The present invention relates generally to solar energy conversion devices to generate power output and particularly to solar collector roof panels used therein.
Typical solar energy conversion devices of the type known as a “solar chimney” use a solar collector built from several transparent roof panels to transmit solar radiation therethrough. Solar energy transmitted by the solar collector heats a fluid, typically air, contained within the solar energy conversion device. The resulting thermal energy in the fluid is converted to kinetic energy to maintain a convective updraft between the solar collector and a chimney, and this kinetic energy is used to drive a turbine coupled to a generator to produce power output.
The solar collector should desirably have sufficient thermal insulation to retain the thermal energy within the fluid while enabling efficient transmission of solar radiation thereto. However, conventional solar collectors typically comprise modular glass panels having poor thermal insulation properties. Solar collectors generally have relatively large surface area to ensure adequate thermal performance of the solar collector. For example, a solar collector design for a typical 200 megawatt power station has typically about 5 Km overall diameter so as to operate at an estimated overall efficiency level of about 70%. Such solar collectors should be substantially reinforced with adequate support structure at appropriate span lengths to maintain overall structural integrity when exposed to the substantial load caused by wind impinging on the large surface of the collector. Fabricating and maintaining a solar-energy-based power plant made from modular glass solar collectors require substantial capital investment, which adversely affects cost effectiveness of power generated by the plant.
Solar collectors fabricated from roof panels comprising thin polymer films have been contemplated. In such a design, overall thermal insulation of the solar collector is enhanced to a certain extent, but in practice maintaining structural integrity of the roof panel comprising such thin polymer film poses a challenge, particularly when the solar collector is subjected to substantial wind load.
Accordingly, there is a need in the related art to address enhancement of performance of the solar collector while minimizing size and weight to render overall cost effectiveness, without compromising structural integrity of the solar collector assembly.